This invention relates to a device for locking a cutting tool machine. The locking device is similar in some respects to locking devices shown in U.S. Pat. No. 3,118,345to Bullard et al, U.S. Pat. No. 3,311,024 to J. Daugherty, U.S. Pat. No. 3,730,637 to V. Cellini, U.S. Pat. No. 4,758,122 to H. Kubo, and U.S. Pat. No. 4,906,147 to Friesinger et al.
The locking device of the present invention is designed to achieve a secure locking of the tool to the cutting machine, with a relatively strong axial holding force; a screw thread frictional force augments the axial lock force. The tool is received within an axially-extending pocket in the exposed face of a holder that forms part of the machine; a bayonet lock system is combined with a threaded puller (clamping) mechanism to securely retain the tool against axial dislocation out of the pocket. Radial and circumferential loads are transmitted from the tool directly to the holder. Axial loads are transmitted from the tool through the threaded clamping mechanism to the holder; the clamping mechanism is required to handle only the axial loads.
During the process of locking the tool to the holder a drawbar is rotated to cause a lock pin to enter into a bayonet slot means carried by the tool. Rotation of the drawbar moves the pin into the blind end of the bayonet slot, after which a nose piece has a screw motion along the drawbar to pull the lock pin axially so as to produce an axial clamp action between the tool and holder. The tool has a tapered shank that wedges into the holder to provide a very secure connection between the tool and holder. To unlock the tool from the holder the drawbar is rotated in a reverse direction so that the nose piece has a reverse screw travel along the drawbar; the lock pin exerts an axial force on the tool to unseat it from the holder.